19 CFR 191.5: Guantanamo Bay, insular possessions, trust territories.

Guantanamo Bay Naval Station is considered foreign territory for drawback purposes and, accordingly, drawback may be permitted on articles shipped there. Drawback is not allowed, except on claims made under 19 U.S.C. 1313(j)(1), on articles shipped to the U.S. Virgin Islands, American Samoa, Wake Island, Midway Islands, Kingman Reef, Guam, Canton Island, Enderbury Island, Johnston Island, or Palmyra Island. Puerto Rico is not considered foreign territory for drawback purposes and, accordingly, drawback may not be permitted on articles shipped there from elsewhere in the customs territory of the United States.